using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Aiwaz.Contracts;
using Aiwaz.Core;
using SlimDX.Direct3D10;
using Aiwaz.Resources.Attributes;

namespace Aiwaz.Resources
{
    [CreationParameters("Create an empty texture")]
    public class EmptyTextureParams : ICreationParams
    {
        public int Width;
        public int Height;
        public int Elements;
        public int MipLevels;
        public SlimDX.DXGI.Format Format;
        public ResourceUsage AccessType;
        public TextureInitialData InitialData;
        public bool RenderTarget;
        public int MultiSampleCount;
        public int MultiSampleQuality;

        public EmptyTextureParams()
        {
            Width = 512;
            Height = 512;
            Elements = 1;
            MipLevels = 1;
            Format = SlimDX.DXGI.Format.Unknown;
            AccessType = ResourceUsage.Default;
            InitialData = null;
            RenderTarget = false;
            MultiSampleCount = 0;
            MultiSampleQuality = 0;
        }
    }

    [CreationParameters("Load a texture from file")]
    public class FileTextureParams : ICreationParams
    {
        [RequiredParameter]
        public string FileName;
        public SlimDX.Direct3D10.ResourceUsage AccessType;

        public FileTextureParams()
        {
            AccessType = ResourceUsage.Default;
        }
    }

    [AiwazResource("Texture", "A placeholder of multidimensional data")]
    public class Texture : ShaderParameterSet, ITexture
    {
        #region ITexture Members

        private string bindingName = "Diffuse";
        private SlimDX.Direct3D10.Resource resource;
        private int lockedSubResource = 0;
        private bool isLocked = false;
        private ResourceUsage accessType;

        private Texture()
            : base(3)
        {
        }

        public Texture(FileTextureParams descriptor)
            : this()
        {
            Console.WriteLine(string.Format("Creating Texture ({0})..", descriptor.FileName));

            this.LoadFromFile(descriptor.FileName, descriptor.AccessType);
            this.WellKnownName = descriptor.FileName;
        }

        public Texture(EmptyTextureParams descriptor)
            : this()
        {
            this.CreateTexture(descriptor.Width, descriptor.Height, descriptor.MipLevels, descriptor.Elements, descriptor.Format, descriptor.InitialData, descriptor.AccessType, descriptor.RenderTarget, descriptor.MultiSampleCount, descriptor.MultiSampleQuality);
        }

        public string BindingName
        {
            get { return bindingName; }
            set
            {
                if (!string.IsNullOrEmpty(bindingName))
                    this.RemoveParameter(bindingName);

                bindingName = value;;

                if (!string.IsNullOrEmpty(bindingName))
                    this.SetParameter(bindingName, this, ParameterBindType.BindBySemantic);
            }
        }

        public int TextureWidth { get; protected set; }

        public int TextureHeight { get; protected set; }

        public int TextureArraySize { get; protected set; }

        public SlimDX.DXGI.Format TextureFormat { get; protected set; }

        public SlimDX.Direct3D10.ShaderResourceView ResourceView { get; protected set; }

        public SlimDX.Direct3D10.Texture2D Texture2D { get; protected set; }

        public SlimDX.DataRectangle MapTextureBuffer(SlimDX.Direct3D10.MapMode mode)
        {
            return this.MapTextureBuffer(mode, 0);
        }

        public SlimDX.DataRectangle MapTextureBuffer(SlimDX.Direct3D10.MapMode mode, int arrayElement)
        {
            if (isLocked)
                throw new ActionFailedException("Texture is already locked.");
            isLocked = true;
            lockedSubResource = arrayElement;

            return this.Texture2D.Map(arrayElement, mode, SlimDX.Direct3D10.MapFlags.None);
        }

        public void UnmapTextureBuffer()
        {
            if (!isLocked)
                return;
            isLocked = false;
            this.Texture2D.Unmap(lockedSubResource);
        }

        private void LoadFromFile(string fileName, SlimDX.Direct3D10.ResourceUsage accessType)
        {
            this.accessType = accessType;
            Engine.FileSystem.Attach(fileName, OnFileChanged);
            this.TextureArraySize = 0;
        }

        private void OnFileChanged(System.IO.Stream stream)
        {
            if (this.Texture2D != null)
                this.Texture2D.Dispose();

            if (this.ResourceView != null)
                this.ResourceView.Dispose();

            var loadInfo = SlimDX.Direct3D10.ImageLoadInformation.FromDefaults();

            if (accessType == SlimDX.Direct3D10.ResourceUsage.Staging)
            {
                loadInfo.BindFlags = 0;
                loadInfo.Usage = SlimDX.Direct3D10.ResourceUsage.Staging;
                loadInfo.CpuAccessFlags = SlimDX.Direct3D10.CpuAccessFlags.Write | SlimDX.Direct3D10.CpuAccessFlags.Read;
            }
            else if (accessType == SlimDX.Direct3D10.ResourceUsage.Dynamic)
            {
                loadInfo.Usage = SlimDX.Direct3D10.ResourceUsage.Dynamic;
                loadInfo.CpuAccessFlags = SlimDX.Direct3D10.CpuAccessFlags.Write;
            }

            using (stream)
            {
                this.Texture2D = SlimDX.Direct3D10.Texture2D.FromStream(Engine.Device, stream, (int)stream.Length, loadInfo);
                resource = this.Texture2D;
            }

            if (accessType != SlimDX.Direct3D10.ResourceUsage.Staging)
            {
                var texViewDesc = new SlimDX.Direct3D10.ShaderResourceViewDescription();

                texViewDesc.Format = this.Texture2D.Description.Format;
                texViewDesc.Dimension = SlimDX.Direct3D10.ShaderResourceViewDimension.Texture2D;
                texViewDesc.MostDetailedMip = 0;
                texViewDesc.MipLevels = this.Texture2D.Description.MipLevels;

                this.ResourceView = new SlimDX.Direct3D10.ShaderResourceView(Engine.Device, this.Texture2D, texViewDesc);
            }

            this.TextureWidth = this.Texture2D.Description.Width;
            this.TextureHeight = this.Texture2D.Description.Height;
            this.TextureFormat = this.Texture2D.Description.Format;
        }

        internal void CreateRenderTargetTexture(int width, int height, SlimDX.DXGI.Format format, int multiSampleCount, int multiSampleQuality)
        {
	        this.CreateTexture(width, height, 1, 0, format, null, SlimDX.Direct3D10.ResourceUsage.Staging, true, multiSampleCount, multiSampleQuality);
        }

        private void DisposeInternal()
        {
            if (this.ResourceView != null)
                this.ResourceView.Dispose();
            this.ResourceView = null;

            if (this.resource != null)
                this.resource.Dispose();
            this.resource = null;
            this.Texture2D = null;
        }

        private void CreateTexture(int width, int height, int mipLevels, int elements, SlimDX.DXGI.Format format, TextureInitialData initialData, SlimDX.Direct3D10.ResourceUsage accessType, bool renderTarget, int multiSampleCount, int multiSampleQuality)
        {
            Console.WriteLine(string.Format("Creating Texture ({0}x{1} {2})..", width, height, format.ToString()));

	        this.DisposeInternal();

             // calculate the needed amount of mipmap levels
	        int mipMapLevels = 1;
	        for (int tmp = Math.Min(height, width); tmp > 1; tmp /= 2, ++mipMapLevels);
	        mipMapLevels = Math.Max(1, Math.Min(mipMapLevels, mipLevels == 0 ? mipMapLevels : mipLevels));

	        // create the resource
            var texDesc = new SlimDX.Direct3D10.Texture2DDescription();
	        texDesc.Width = width;
	        texDesc.Height = height;
	        texDesc.MipLevels = mipMapLevels;
	        texDesc.ArraySize = Math.Max(1, elements);
	        texDesc.Format = format;
            texDesc.SampleDescription = new SlimDX.DXGI.SampleDescription(multiSampleCount, multiSampleQuality);

	        if (accessType == SlimDX.Direct3D10.ResourceUsage.Dynamic)
	        {
		        texDesc.Usage = SlimDX.Direct3D10.ResourceUsage.Dynamic;
		        texDesc.CpuAccessFlags = SlimDX.Direct3D10.CpuAccessFlags.Write;
	        }

	        if (accessType == SlimDX.Direct3D10.ResourceUsage.Staging)
		        texDesc.BindFlags = ((mipMapLevels > 1 || renderTarget) ? SlimDX.Direct3D10.BindFlags.RenderTarget : SlimDX.Direct3D10.BindFlags.None) | SlimDX.Direct3D10.BindFlags.ShaderResource;
	        if (mipMapLevels > 1)
		        texDesc.OptionFlags = SlimDX.Direct3D10.ResourceOptionFlags.GenerateMipMaps;

            resource = this.Texture2D = new SlimDX.Direct3D10.Texture2D(Engine.Device, texDesc);

	        // create the resource view when possible
	        if (accessType != SlimDX.Direct3D10.ResourceUsage.Staging)
	        {
                var texViewDesc = new SlimDX.Direct3D10.ShaderResourceViewDescription();
		        texViewDesc.Format = texDesc.Format;
		        texViewDesc.ElementWidth = elements;

		        if (elements > 0)
			        texViewDesc.Dimension = multiSampleCount == 1 ? SlimDX.Direct3D10.ShaderResourceViewDimension.Texture2DArray : SlimDX.Direct3D10.ShaderResourceViewDimension.Texture2DMultisampledArray;
		        else
			        texViewDesc.Dimension = multiSampleCount == 1 ? SlimDX.Direct3D10.ShaderResourceViewDimension.Texture2D : SlimDX.Direct3D10.ShaderResourceViewDimension.Texture2DMultisampled;

		        texViewDesc.MostDetailedMip = 0;
		        texViewDesc.MipLevels = texDesc.MipLevels; 
		        texViewDesc.ArraySize = elements;

                this.ResourceView = new SlimDX.Direct3D10.ShaderResourceView(Engine.Device, resource, texViewDesc);
	        }

	        // finalize
	        this.TextureWidth = width;
	        this.TextureHeight = height;
	        this.TextureFormat = format;
	        this.TextureArraySize = 1;

	        this.BindingName = this.BindingName;
        }

        #region IDisposable Members

        public override void Dispose()
        {
            this.DisposeInternal();
            base.Dispose();
        }

        #endregion


        #endregion
    }
}